// ECMAScript标准提供的内置对象有：
let b: Boolean = new Boolean(1);
let e: Error = new Error('Error occurred');
let d: Date = new Date();
let r: RegExp = /[a-z]/;

// DOM和BOM的内置对象
// let body: HTMLDocument = document.body;
let allDiv: NodeList = document.querySelectorAll('div');
document.addEventListener('click', function(e: MouseEvent){
  // Do something
});
